1. Field of the Invention
The present invention relates to cookware and more particularly to cooking vessels fabricated from a single piece of sheet metal and to a method for making same.
2. Description of Prior Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Cooking vessels have had some advances in recent years in materials and construction methods, with some improvements leading to some improved cooking performance and/or convenience for consumer cooks. One area that has had very little attention is the cookware used by commercial kitchens and restaurants, with the most common pans still in use being very similar to pans of several hundred years ago in materials and manufacturing methods. The most common commercial pan is the classic French style skillet with pressed steel sheet pan body secured to a strip metal handle most commonly by three rivets.
These pans are still the standard because their bare steel pan surfaces do not wear out, and the natural nonstick ‘seasoning’ built up by cooking with fats and oils can withstand the high heats required of commercial cookery without the chemical breakdown experienced by synthetic coatings at high heat, or the relatively rapid mechanical breakdown from the severe abrasion environment (food chemistry, utensils, cleaning). The metal strip or tube handles are also favored over synthetic handles because commercial cookery techniques often involve transfer of pans from stove to oven, or baking food entirely in the oven at temperatures that rapidly deteriorate or destroy polymer handles.
The limitations inherent in this traditional steel cookware, as observed and discussed with cooks over a period of several decades on several continents, include:                1. Rivets heads in the pan body, joining the handle, are a site for sheltering food residue, being difficult to clean around.        2. Rivets can work loose over time, leading to increasing freeplay between handle and pan body, and occasional catastrophic failure.        3. Traditional narrow strip steel handles are uncomfortable for cooks to handle over long periods of pan work, particularly when a significant proportion of a restaurant cook's pan work involves shuffling the food in the pan by agitating the handle, or the classic sauté toss.        4. Round handles which seem to be comfortable in a static grip can become fatiguing in the abovementioned dynamic situations because there is a significant, and undesired, rotational force (typically from unbalanced food loads during the sauté toss) that needs to be controlled by squeezing the handle to produce the required friction to counter the rotational moment. Narrow strip handles can also be poor in this regard due to their limited leverage in the rotational direction. These forces are rarely perceived by cooks and their strained hands and arms are regarded as a ‘normal’ part of all the movement in their work. Static comfort is relatively easy to achieve, being any shape which feels comfortable when gripped statically by the user. However, dynamic performance and reduction of strain is a different matter, and not as evident. Design to counter the dynamic forces is not apparent in prior art, particularly in the common narrow flat strip steel handles. Less evident is the dynamic deficiency inherent in handles that are too round in cross-section, being apparently designed to maximize static comfort, while being the least optimal for controlling rotational forces (due to the resulting hand strain from the additional squeezing required to generate the necessary friction to control those forces).        5. Many all-metal handle designs (riveted/welded or cast) in the market conduct significant heat up the handle to the zone gripped by the cook's hand. In commercial kitchens cooks usually grip their pans with a cloth or glove to avoid burns from this heat transfer. It would be apparent that a single-piece metal pan would conduct more heat from the pan body up the handle, being one continuous conduit for the conducted heat. This is particularly evident in most cast iron pans with short/thick handles, or in pans with short and thick welded or riveted handles.        6. There exists spot-welded or arc-welded examples of pan-handle joins in commercial cookware, though these are generally not as trusted by cooks for fear of catastrophic spot weld failure, or not as commercially viable in the case of the stronger arc welding methods with higher fabrication costs.        7. A common cookware annoyance for consumers is the tendency for handles with screws to become loose when the screw loosens. A one-pieced formed metal pan eliminates this annoyance.        8. Pan lids can lack durability if they have joined handles, or their handles are made with materials that don't survive high temperatures in ovens. Metal lid handles can become hot on the stove-top.        
There evidently remains scope to improve the hygiene, durability, dynamic handle ergonomics, and handle heating of traditional metal commercial cookware and their lids. An obvious solution for the hygiene and durability limitations discussed above would be to make the pan and handle from a single piece of metal, preferably steel, iron, or stainless steel, to eliminate all joins and seams. Hand- or machine-wrought single piece pans have been known since antiquity, though their artisanal, labor-intensive manufacturing methods have not proven viable for the relatively low-cost cookware demanded in most commercial kitchens, and by most consumers today. Cast iron can produce very suitable one-piece shapes, though the thick sections required for the iron pouring process renders the cookware too heavy for regular prolonged and very physical commercial cookery methods. They are simply too fatiguing for chefs, or for anyone with relatively weak hands or arms.
Though the focus of this invention is to improve cookware for commercial cookery environments, the most demanding environment for cookware, it should be evident that the improvements embodied in this invention would also satisfy the most demanding of home cooks.
In general, it is the purpose of this invention to address the existing perceived deficiencies noted above with a new combination of manufacturing methods and new design features for metal cookware and lids.
It is therefore a prime object of the present invention to provide cookware formed from a single metal sheet and a method for making same.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which there are no rivet heads are present joining the pan body and handle, eliminating a site for sheltering food residue, or which are difficult to clean around.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which there are no rivets that can work loose over time, leading to increasing play between handle and pan body, and occasional catastrophic failure.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the handles are comfortable for cooks to use over long periods of pan work.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the handles are comfortable to use when pan work involves shuffling the food in the pan by agitating the handle, or the classic sauté toss.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the shape of the handles improves the dynamic performance of the pan.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the shape of the handle reduces the strain from use.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the amount of heat which is conducted by the handle from the pan body to the hand grip portion is reduced.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which spot-welding or arc-welding pan-handle joints are eliminated.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which there are no screws that can become loose.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the same manufacturing method can be used to fabricate pan lids with handles with the same advantageous characteristics.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which pan lids with handles have improved durability.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the handles are made with materials that are capable of surviving the high temperatures in ovens.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the lid handles do not become excessively hot on the stove-top.
It is another object of the present invention to provide cookware formed from a single metal sheet and a method for making same in which the same benefits apply equally to frying pans, saucepans, and pots of all types.